import 'dart:ui';

import 'package:flutter/material.dart';
/* - 外部包 */
import 'package:english_words/english_words.dart';

void main() => runApp(new App());

/* - Material App */
class App extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'startup name generator',
      home: new RandomWords(),
      /* - 更改程序主题色 */
      theme: new ThemeData(primaryColor: Colors.green),
    );
  }
}
/*{
  @override
  Widget build(BuildContext context) {
    // final wordPair = new WordPair.random();
    return new MaterialApp(
      title: "welcome to flutter app",
      home: new Scaffold(
        appBar: new AppBar(
          title: new Text('welcome to flutter'),
        ),
        body: new Center(
          // child: new Text('hello world'),
          // child: new Text(wordPair.asPascalCase),
          child: new RandomWords(),
        ),
      ),
    );
  }
}*/

class RandomWordsState extends State<RandomWords> {
  final _suggestions = <WordPair>[]; // 单词对
  final _biggerFont = const TextStyle(fontSize: 18.0); // 字体大小
  final _saved = new Set<WordPair>(); // 收藏单词对

  @override
  Widget build(BuildContext context) {
    // final wordPair = new WordPair.random();
    // return new Text(wordPair.asPascalCase);
    return new Scaffold(
      appBar: new AppBar(
        title: new Text('startup name generator'),
        actions: <Widget>[
          new IconButton(icon: new Icon(Icons.list), onPressed: _pushSaved)
        ],
      ),
      body: _buildSuggestions(),
    );
  }

  void _pushSaved() {
    Navigator.of(context).push(
      new MaterialPageRoute(builder: (context) {
        final tiles = _saved.map(
          (pair) {
            return new ListTile(
              title: new Text(
                pair.asPascalCase,
                style: _biggerFont,
              ),
            );
          },
        );
        final divided =
            ListTile.divideTiles(tiles: tiles, context: context).toList();

        return new Scaffold(
          appBar: new AppBar(
            title: new Text('saved suggestions'),
          ),
          body: new ListView(
            children: divided,
          ),
        );
      }),
    );
  }

  /* 构建显示建议单词对的ListView */
  Widget _buildSuggestions() {
    return new ListView.builder(
        padding: const EdgeInsets.all(16.0),
        itemBuilder: (context, i) {
          if (i.isOdd) return new Divider();
          final index = i ~/ 2;
          if (index >= _suggestions.length) {
            _suggestions.addAll(generateWordPairs().take(10));
          }
          return _buildRow(_suggestions[index]);
        });
  }

  Widget _buildRow(WordPair pair) {
    final alreadySaved = _saved.contains(pair); // 检查单词是否在收藏夹中
    return new ListTile(
      title: new Text(
        pair.asPascalCase,
        style: _biggerFont,
      ),
      trailing: new Icon(
        alreadySaved ? Icons.favorite : Icons.favorite_border,
        color: alreadySaved ? Colors.red : null,
      ),
      onTap: () {
        setState(() {
          if (alreadySaved) {
            _saved.remove(pair);
          } else {
            _saved.add(pair);
          }
        });
      },
    );
  }
}

/* 添加有状态的部件 */
class RandomWords extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => new RandomWordsState();
}
